Abstract:

The identification of five novel compounds, pseudo-erythromycin A-6,9-hemiketal, 8,9-anhydro-pseudo-erythromycin A-6,9-hemiketal, 8,9-anhydro-pseudo-N-demethylerythromycin A-6,9-hemiketal, 5-O-beta-D-desosaminylerythronolide A and 15-nor-erythromycin C, in mother liquor concentrates of Streptomyces erythraeus is described. The pseudo-erythromycin derivatives are characterized by a 12-membered macrocyclic ring as a result of C13––C11 trans-lactonization. The five compounds have very little antimicrobial activity.